An Examination of Weismannism

by George John Romanes

ON TELEGONY.

A widely different view, however, is taken by Mr. Herbert Spencer with regard to the theoretical interpretation of telegony. This, indeed, is precisely the opposite view to the one which is given in the text. For while I agree with Professor Weismann in holding that the facts of telegony (supposing them to be facts) are as compatible with the theory of germ-plasm as with that of gemmules, “physiological units,” or any other theory which postulates a centripetal flow of the carriers of heredity from somatic-cells to germ-cells, Mr. Spencer is of the opinion that these facts are destructive of any theory which postulates a continuity in the substance of heredity—i.e., a centrifugal flow of the carriers of heredity. And, unquestionably, Mr. Spencer’s view is the prevalent one. Therefore, seeing that his opinion is not only of weight per se, but is shared by the scientific world in general, I will here transcribe a somewhat lengthy discussion which I have recently held with him upon the subject.

In the Contemporary Review for March, Mr. Spencer wrote as follows:—

We pass now to evidence not much known in the world at large, but widely known in the biological world, though known in so incomplete a manner as to be undervalued in it. Indeed, when I name it probably many will vent a mental pooh-pooh. The fact to which I refer is one of which record is preserved in the museum of the College of Surgeons, in the shape of paintings of a foal borne by a mare not quite thoroughbred, to a sire which was thoroughbred—a foal which bears the markings of the quagga. The history of this remarkable foal is given by the Earl of Morton, F.R.S., in a letter to the President of the Royal Society (read November 23, 1820). In it he states that wishing to domesticate the quagga, and having obtained a male, but not a female, he made an experiment.

I tried to breed from the male quagga and a young chestnut mare of seven-eighths Arabian blood, and which had never been bred from; the result was the production of a female hybrid, now five years old, and bearing, both in her form and in her colour, very decided indications of her mixed origin. I subsequently parted with the seven-eighths Arabian mare to Sir Gore Ouseley, who has bred from her by a very fine black Arabian horse. I yesterday morning examined the produce, namely, a two-year-old filly and a year-old colt. They have the character of the Arabian breed as decidedly as can be expected, where fifteen-sixteenths of the blood are Arabian; and they are fine specimens of that breed; but both in their colour and in the hair of their manes they have a striking resemblance to the quagga. Their colour is bay, marked more or less like the quagga in a darker tint. Both are distinguished by the dark line along the ridge of the back, the dark stripes across the fore-hand, and the dark bars across the back part of the legs[75].

Lord Morton then names sundry further correspondences. Dr. Wollaston, at that time President of the Royal Society, who had seen the animals, testified to the correctness of his description, and, as shown by his remarks, entertained no doubt about the alleged facts. But good reason for doubt may be assigned. There naturally arises the question—How does it happen that parallel results are not observed in other cases? If in any progeny certain traits not belonging to the sire, but belonging to a sire of preceding progeny, are reproduced, how is it that such anomalously-inherited traits are not observed in domestic animals, and indeed in mankind? How is it that the children of a widow by a second husband do not bear traceable resemblances of the first husband? To these questions nothing like satisfactory replies seem forthcoming; and, in the absence of replies, scepticism, if not disbelief, may be held reasonable.

There is an explanation, however. Forty years ago I made acquaintance with a fact which impressed me by its significant implications; and has, for this reason I suppose, remained in my memory. It is set forth in the Journal of the Royal Agricultural Society, vol. xiv. (1853), pp. 214 et seq., and concerns certain results of crossing English and French breeds of sheep. The writer of the translated paper, M. Malingié-Nouel, Director of the Agricultural School of La Charmoise, states that when the French breeds of sheep (in which were included “the mongrel Merinos”) were crossed with an English breed, “the lambs present the following results. Most of them resemble the mother more than the father; some show no trace of the father.” Joining the admission respecting the mongrels with the facts subsequently stated, it is tolerably clear that the cases in which the lambs bore no traces of the father were cases in which the mother was of pure breed. Speaking of the results of these crossings in the second generation “having seventy-five per cent. of English blood,” M. Nouel says:—“The lambs thrive, wear a beautiful appearance, and complete the joy of the breeder.... No sooner are the lambs weaned than their strength, their vigour, and their beauty begin to decay.... At last the constitution gives way ... he remains stunted for life”: the constitution being thus proved unstable or unadapted to the requirements. How, then, did M. Nouel succeed in obtaining a desirable combination of a fine English breed with the relatively poor French breeds?

He took an animal from “flocks originally sprung from a mixture of the two distinct races that are established in these two provinces [Berry and La Sologne],” and these he “united with animals of another mixed breed, ... which blended the Tourangelle and native Merino blood of” La Beauce and Touraine, and obtained a mixture of all four races “without decided character, without fixity, ... but possessing the advantage of being used to our climate and management.”

Putting one of these “mixed-blood ewes to a pure New-Kent ram ... one obtains a lamb containing fifty-hundredths of the purest and most ancient English blood, with twelve and a-half hundredths of four different French races, which are individually lost in the preponderance of English blood, and disappear almost entirely, leaving the improving type in the ascendant.... All the lambs produced strikingly resembled each other, and even Englishmen took them for animals of their own country.”

M. Nouel goes on to remark that when this derived breed was bred with itself, the marks of the French breeds were lost. “Some slight traces could be detected by experts, but these soon disappeared.”